Photographic enlarging and printing machine



July 26, 1938. P. s PIRMOV PHOTOGRAPHIC ENLARGING AND PRINTING-MACHINE 2Sheets-Sheet l lmvezziozw PauZ @Ba'wmaa Patented July 26, 1938 UNITEDSTATES PATENT OFFICE PHOTOGRAPHIC ENLARGING AND PRINT- ING 'MACHINEApplication February 14, 1935, Serial No, 6,531

8 Claims.

This invention relates to photo enlarging and printing machines of thetype where the enlarged print is made directly on sensitized paper fromnegatives, which latter may be either in the form of cut or strip films.

The object of the invention, among other things, is to so improve thefacility with which the successive steps of printing may be carried outas to increase both the rapidity and simplicity of operation and toinsure a more accurate and faithful reproduction.

The invention will be best understood by reference to the followingdescription when taken in connection with the accompanying illustrationof one specific embodiment thereof, while its scope will be moreparticularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a front elevation of a machine embodying one form of theinvention, showing the movable parts in the open or raised positionpreparatory to printing;

Fig. 2 is a sectional elevation on the line 2-2 in Fig. 1;

Fig. 3 is a sectional elevation on an enlarged scale showing the filmsupporting table with the principal movable parts in a depressedposition just prior to printing;

Fiy. 4 is a similar sectional elevation showing the subsequent positionof the parts at the instant of printing; and

Fig. 5 is a perspective, with the visor and lens shutter removed,showing the negative resting operator. I

Referring to the drawings and to the embodiment of the invention thereinshown for purposes of illustration, the latter comprises a film ornegative supporting table l0 having a fiat top and fixedly secured onand between two upright posts l2, the latter being supported by the basel4 adapted to rest on the floor. The table is fixed at a heightconvenient to the operator for viewing on the film supporting table asit appears to the by the paper clamp 22 in flattened and prefocusedposition on a transparent glass or image receiving plate 24 covering anaperture in the paper supporting table 26. The latter is also secured tothe upright posts l2 above the film supporting table H) but adjustablevertically on the posts by means of clamping screws 28 to vary, ifdesired, the scale of enlargement or desired ratio of magnification.

In prior machines of this general class, the rapidity of printing hasbeen seriously hampered by the fact that attempts to shorten the time ofexposure by increasing the intensity of illumination have resulted inabnormally increasing the heat accompanying the high power illumination,which, in proximity to the film, tends to overheat or even burn orscorch the negative. This hasenforced the use of supersensitive paperwith relatively low candle powerillumination and has been commonlyconfined to such illumination as arises, for example, from an electriclamp of from 100 to 150 watts capacity. One object of the invention isto provide greatly intensified illumination, such, for example, as isrepresented by an electric lamp of from 1000 to 1500 watts or more, thisbeing employed under such conditions that no detrimental heating efiecton the negative takesplace and such that paper of ordinary sensitivenessmay be employed with an equally low or even lesser time required forexposure.

Herein the illumination is provided by a high candle power electric lamp30, which, as stated, may be of from 1000 to 1500 watts capacity, thisbeing enclosed within and supported at the bottom of a cylindricalcasing 32 at the back of the machine and constituting a part of thelight box or housing. By the side of the lamp there is also provided alamp 34 of low candle power, such, for example, as 10 watts, the latterbeing permanently in circuit and employed for the purpose of creating afaint illumination sufficient to examine and position the negativepreparatory to printing, the lamp 30 being cut into circuit only at theinstant of printing to project the image on the sensitized paper. 4

The lamp casing 32 is provided with an open, laterally extending,conical throat 3B, in the mouth of which ispositioned a condensing lensto receive the light rays from the lamp and project them in parallelismagainst a mirror 42. The latter is held at the end of the extension 38in such position and at such an angle as to receive the light rays fromthe lens 40 and project them upwardly in parallelism with a verticalaxis passing through the center of the aperture l8 of the film table andthe focusing lens 20.

housing is fixedly carried thereby with the lamp compartment 32 inlateral overhanging relation well removed at the rear of the machineaway from the vertical axis of the lens and out of proximity to thenegative. 1

To conduct the heat generated by the lamps still further away from anypoint where it might and other parts within the housing. Preferably anair space is provided back of the mirror 12, the backing plate 5%therefor having one or more openings for circulation ofair about themirror.

Another object of the invention is to insure precision in the positionand adjustment of the fo cusing lens at all times, to maintain the filmwithin the field of vision of the operator and to facilitate and assurethe accurate position of the film fiatwise on the glass covered aperturein the table. To secure these results the-film or negative is maintainedwithin the vision of the operator up to and even during the time ofexposure so that its adjustment and condition may at all times beobserved.

To this end the enlarging lens 2@, mounted in the usual slidinglens-holding sleeve for purposes of focal adjustment, is carried in thetubular walls of a lens carrier comprising the plate-53 above andoverhanging the table ES and supported by the inclined arm or plate 6%which is fixedly secured to the table. Accordingly the lens holder ismaintained immovable at all times and in a fixed established positionduring the successivesteps of the printing operation and, when the lensis once adjusted, no further attention is required thereto, the onlymovable elements in immediate proximity to the negative being thosecomprising the relatively light negative clamping and compressing meansabout to be described and which is applied to the negative just. priorto the time of exposure. I

Such clamping means herein comprises the light rectangular metal frame62 (Figs. 1 and 2) hinged at its rear end to the table. This is normallyheld tilted up in raised position (as shown in Fig. 2), but through theactuating mechanism hereinafter described, may be depressed down againstthe film (as shown in Figs. 3 and 4). The frame is pivoted at its rearend on a pin or rod 64 which is carried by the opposite .frame-hingingwalls 86, the latter being herein formed as parts of the fixed lenscarrier to impart stiffness and rigidity thereto and also serving asguiding walls to guide the frame in its rocking movement.

It will be seen that these walls 66 rest on and contact with the tableill at the rear of the glass plate but diverge upwardly and forwardlytherefrom so as to interfere at no time either with the free shifting ofthe negative over the table or with the free open vision of the operatorin view-' ing the film, which vision (as indicated in Fig. 5) isunobscured at all times by the lens carrier.

Within the rectangular opening of the frame 82 there is held atransparent glass panel 68 with beveled edges which seat againstsimilarly beveled walls in the frame. held to its seat in the frame bytwo springs l0 carried by upturned ears F2 on opposite sides of theframe and engaging the back ortop of the panel along its opposite sidesbut leaving an intermediate unobstructed transparent area in the panelequal at least to the maximum area on the negative from which it may bedesired to print.

The face or underside of the glass panel normally projects slightlybelow the underside of the rectangular frame so that, when the frame isdepressed (as hereinafter described) the glass panel has prior contactwith the film or negative to be printed and, as pressure is continued,yields The glass panel is yieldably slightly in the frame. This acts tosqueeze the film between the two transparent surfaces, that of the glassplate l6 and that of the glass panel 68, compressing the film andleaving it in a completely flattened state free from any condition ofbuckling or the like. sharpness in the projectness of the image on thesensitized paper which is otherwise unobtainable. The application ofsuch film contacting and compressing device also serves to cool the filmby conduction in the event of unusually long exposures to the lightrays, additionally reducing any danger from overheating the film. In theevent of the use of a mat or mask over the film, such'mat or mask isordinarily so thin that the This insures a uniform clamping andcompressing action of the glass .panel 58 is substantially as described.

To raise or lower the frame 62, the latter has a forwardly projectingarm it which is pivotally connected at it to an upright verticallymovable actuating rod it. This rod is mounted for sliding movement in acollar 8@ carried by the arm 82 pivoted on a sleeve member 86 fastenedto one of the posts 82. The collar 89 is carried by a pin 86 having alimited movement in a slot in the arm 82 to permit the necessarydepression of the arm without binding. Near its upper end the rod l8also has sliding movement through a second collar 88 secured to an arm96 projecting forwardly fromone side of the pivoted paper clamp 22. Anarm extending rearwardly from the pivot of the paper clamp carries acounterweight M which serves normally to maintain the parts in theposition shown in Fig. 2 and to re-v store them to that position whenthe rod 78 is free to rise.

Slidably mounted on the rod it is' a knob or handle 92 at a heighteasily accessible to the operator and through which the depression ofthe rod and the frame 62 is effected. On the rod 78 below the collar 88there is provided a fixed abutment 9 1 and between the abutment and thecollar also a coiled spring 96. On depression of the knob, the latterengages the collar moving the collar downward with its attached arm 82,and,- acting through the spring and the abutment 96, depresses the rodand swings the film clamping frame down from the position shown in Figs.1 and 2 to that shown in Fig; 3, compress ing and flattening the film.Further downward movement of the knob additionally compresses the springand increases the pressure on the film plate, the parts then moving fromthe position shown in Fig. 3 to that shown in Fig. 4.

over the image-receiving plate 24.

The depression of the rod I8 and the film plate 62 is accompanied by asimilar downward movement of the paper compressing plate 22. This isprovided for by the interposition of a coiled spring 98 on the rod I8between the collar 88 and a fixed abutment I on the rod above thecollar.

The paper clamp comprises a backing or carrier plate 22 hinged at itsrear end to the paper supporting table 26 and carrying a presser plateI06 which is yieldably supported thereon with a certain amount of lostmotion. This is provided by studs I08 encircledeach by a coiled springH0 normally holding the presser plate slightly away from the backingplate. When the latter is swung down by the depression of the rod, thepresser plate overlies and engages the sensitized paper which haspreviously been placed This acts to press the paper flat, the pressurebeing increased as the knob is moved down to its final position shown inFig. 4.

The depression of the knob to the final position shown in Fig. 4 notonly depresses the negative and paper clamps, clamping and flatteningboth the film and the paper, but is herein utilized simultaneously toclose the circuit through the,

high power lamp 30. This may be accomplished in any desired manner butherein there is indicated more or less diagrammatically a switch box II2 secured to the sleeve member 84 on the post I2 carrying spacedcontacts IIG normally holding open the lamp circuit. These contacts areadapted to be closed, however, by the bridging member H6 normallydepressed by a spring but adapted to be lifted to close the switch whenengaged by the rearwardly'projecting end of the lever 82 when it risesto the substantially ho-rizontal position shown in Fig. 4. Thiscorresponds to the finally depressed position of the knob 92 and rod I8and is contemporaneous with and maintained during the period ofexposure.

As soon as pressure is relieved on the knob 92, the lever 82 swings fromthe position shown in Fig. 4 to that shown in Fig. 3, instantly breakingthe lamp circuit. The period during which the knob is held depressed (asshown in Fig. 4)

measures the interval during which exposurecontinues and may of coursebe accurately timed.

A feature which renders uncertain the effective period of exposure wherean electric lamp is employed is the afterglow of the lamp following thebreaking of the lamp circuit. This is apt to be particularly troublesomein the case of high wattage lamps. Such afterglow ofen results in anover exposure due to the persistence of the image projecting lightbeyond the intended timing. It may also produce a double image or l ghtstreaks on the sensitized paper, particularly under high speeds ofoperation, caused by the persistence of light after the film or paper orboth have been subject to some slight displacement, such as might occurin the described machine after the release stroke of the paper and filmclamping plates has been initiated.

To elimina e the detrimental eiiect of such afterglow or displacement ofthe paper or negative before the light can be cut off, there is hereprovided means for interposing an opaque wall or shutter in the path ofthe light rays. Such shutter is automatically wihdrawn from that pathwhen exposure is designed to start, as determined by the finaldepression of the knob 92 (Fig. 4), but is automatically re-establishedin thatpath the instant the predetermin d time of exposure has elapsed,as determined by the release of the knob and its upward movement.

This is most conveniently provided in the form of a thin metallic plateH8 and most conveniently positioned immediately above the lens 20 insuch relationship that it may be moved over the lens to cut off alllight rays transmitted upwardly therefrom (Figs. 2 and 3), or may bemoved reversely to permit the transmission of such light rays Withoutinterference (Fig. 4).

Herein the shutter plate H8 has a portion l20 bent at right anglesthereto, the opposite end of which is secured to a horizontal,transverse, rocking rod I 22 mounted for turning movement in the twoears I24 which are formed on the opposite frame-hinging walls- 66, theshutter being normally urged to its light interrupting position (Figs. 2and 3) by a torsion spring I26 (Fig. 1). To rock the shutter, the rodI22 carries at one end an upwardly and forwardly projecting pin- I28having a laterally bent end lying within the path of the arm 82, the pinbeing presented at such an angle that when engaged by the arm it isswung forwardly and downwardly rocking the shutter from the closed orlight-interrupting position (Fig. 3) to the open or light-unobstructingposition (Fig. 4).

Accordingly, in the normal raised position of the clamping plates, theshutter is closed as shown in Fig. 2 and remains closed until and afterthe clamping plates are applied as shown in Fi 3.

In the ensuing downward stroke of the rod 18, the shutter is slowlyrocked toward open position so that when the rod reaches the end of itstravel, with the resulting increased pressure on the clamping plates andthe final closing of the lamp circuit, the shutter has been withdrawnentirely out of the path of the light transmitted by the lens. On therelease of the knob, however, and the first upward motion of the rod IS,the shutter snaps back to the closed position, cutting on the passage oflight from the lens to the sensitized paper.

To permit the operator to view without. eye fatigue, if desired, thebrightly illuminated negative during its exposure to light from the highwattage lamp, there may be provided a visor or anti-glare element i136,normally positioned out of the field of vision of the operator inlooking at the negative, but adapted to be moved at the time of exposureinto such position as to interpose such element within his normal lineof vision. Such visor may be in the form of a plate of colored, cloudedor semi-transparent material such as Celluloid or glass.

To provide for its required movement, it is herein attached to theshutter actuating rod l22 and projects therefrom at such an angle thatprior to the instant of exposure it occupies the position shown in Figs.2 and 3, where there is no interference with the operators clear visionof the negative. In Fig. 1 the visor is shown broken away at the left toleave visible the spring H26. At the instant of exposure, however, it isswung down to such a position, as shown in Fig. 4, that the operator inhis normally assumed attitude may without eye strain view'the brightlyilluminated field of the negative through the visor. The visor may be ofsuch size or area as to entirely screen or dull the bright illuminationtransmitted from the negative in the direction of the operator, or itmay be of such size as to interrupt only the rays reaching him in thenormal position of his head, so that by inclining or moving his head hemay, should he so desire, still view the brilliantly lighted negativefrom beneath or around the sides of the visor.

The operation of the machine, which is carried out in the usualphotographers dark room or its equivalent, will be readily understoodfrom the previous description of the parts and their functions, but maybe briefly summarized as follows.

With the parts in position shown in Figs. 1 and 2 and the paper andnegative clamping members raised, the negative (herein shown in strlpform and indicated at H32 in Fig. is placed on the fiat table it overthe transparent plate iii where its image becomes visible through therelatively feeble illumination aiforded by the constantly burning lowwattage lamp 35. This enables the operator to judge of the density andquality of the negative and estimate the required time for exposure, aswell as to adjust it in properly aligned position.

Normally the negative will be covered by an opaque mask or mat, such asi3 3 (Fig. 5), formed of thin sheet-metal, paper or other material andcut to a size suited for the size of the negative. The mask beingsuitably positioned on the table it, the negative is then quicklyadjusted to the proper position as defined by the mask.

Immediately following the adjustment of the negative, the operatorplaces the sensitized paper face down against the top of the transparentimage receiving plate 26 and presses the rod 78 by the knob 92, bringingthe parts to the position shown in Fig. 3. In that position the paper.

and the negative have been clamped, compressed and flattened by theirrespective clamping members but the shutter still remains closed and.the visor tilted up. This gives opportunity to view the negative andcheck its finally clamped position before exposure.

The knob is then finally depressed, bringing the parts as shown in Fig.4, simultaneously lighting the high power lamp, withdrawing the shutter,lowering the visor and causing the image to be projected on thesensitized paper, the knob being held depressed for an intervalconforming to the predetermined time of exposure.

The knob is then released, this serving instantly and simultaneously tocut out the lamp 30, close the shutter and raise the visor, this beingthen followed by the tilting up of the clamping plates on the succeedingupward movement of the rod and the knob. The paper is then removed andreplaced by another piece, and the operation repeated with a differentnegative or with the same negative, as may be desired. These successivesteps may be carried out with great rapidity but with the assurance thata clean cut exposure is had through the flattened negative, while at thesame time the position of the negative is at all times within theobservation of the operator.

While I have herein shown and described for the purposes of illustrationone specific embodiment of the invention, it is to be understood thatextensive deviations may be made in the form and mechanical arrangementof the parts herein illustrated and that extensive changes may be madetherefrom, all withoutdeparting from th spirit of the invention.

I claim:

1. In a photographic enlarging and printing machine, a transparent fiat.support against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from areaeta said support, asource of illumination sufficient to render visible to the operator theimage on a negative placed on said transparent fiat support, means forintensifying the illumination'for purposes of exposure, side walls and aback wall projecting downwardly from said enlarging lens and largelyencompassing space in the line of vision of the operator between saidsupport and said enlarging lens to confine largely through said lens thelight emanating from said source of illumination, a movable shutternormally in the path of the light emanating from said lens, a movableshield for largely blocking oif light from the front of said encompassedspace, said shield being movable out of light-blocking position to leavethe negative fully exposed to the view of the operator while said sourceof illumination is in non-intensified condition and being movable intolight-blocking position while said source of illumination isintensified, means for simultaneously withdrawing the shutter from thepath of the light emanating from said lens and for moving said shieldinto light-blocking position. and a single manuallymanipulable means foractuating said last-named means.

2. In a photographic enlarging and printing machine, a transparent flatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source ofillumination suficient to render visible to the operator the image on anegative placed on said transparent flat support, means for intensifyingthe illumination for purposes of exposure, side walls and-a back wallprojecting downwardly from said enlarging lens andlargely encompassingspace in the line of vision of the operator between said support andsaid enlarging lens to confine largely through said lens the lightemanating from said source of illumination, a movable shutter normallyin the path of the light emanating from said lens,-a movable shield forlargely blocking ofi light from the front of said encompassed space,said shield being movable out of light-blocking position to leave thenegative fully exposed to the view of the operator while said source ofillumination is in nonintensified condition and being movable intolight-blocking position while said source of illumination isintensified, means for withdrawing the shutter from the path of thelight emanating a negative may be placed, an enlarging lens immovablyfixed in spaced relationship from said support, a source of illuminationsufiicient to render visible the image on the negative, means forintensifying the illumination for purposes of exposure, side walls and aback wall projecting downwardly from said enlarging lens and largelyencompassing space in the line of vision of the operator between saidsupport and said enlarging lens to confine largely through said lens thelight emanating from said source of illumination, a movable shutternormally in the path of the light emanating from said lens, a movableshield for largely blocking oif light from the front of said encompassedspace but permitting view therethrough of the highly illuminatednegative, said shield being movable out of light-blocking position toleave the negative fully exposed to the view of the operator while saidsource of illumination is in non-intensified condition and being movableinto light-blocking position while said source of illumination isintensified, and means for simultaneously withdrawing the shutter fromthe path of the light emanating from said lens and for moving saidshield into lightblocking position.

4. In a photographic enlarging and printing machine, a transparent fiatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source ofillumination sufiicient to render visible the image on the negative,means for intensifying the illumination for purposes of exposure, sidewalls and a back wall projecting downwardly from said enlarging lens andlargely encompassing space in the line of vision oi the operator betweensaid support and said enlarging lens to confine largely through saidlens the light emanating from said source of illumination, a movableshutter normally in the path of the light emanating from said lens, amovable shield for largely blocking off light from the front of saidencompassed space but permitting view therethrough of the highlyilluminated negative, said shield being movable out of light-blockingposition to leave the negative fully exposed to the view of the operatorwhile said source of illumination is in non-intensified condition andbeing movable into light-blocking position while said source ofillumination is intensified, and means for withdrawing the shutter fromthe path of the light emanating from said lens and for moving saidshield into light-blocking position simultaneously with theintensification of said source of illumination.

5. In a, photographic enlarging and printing machine, a transparent fiatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source ofillumination sufilcient to render visible to the operator the image on anegative placed on said transparent fiat support, means for intensifyingthe illumination for purposes of exposure, walls projecting downwardlyfrom said enlarging lens and substantially encompassing space in theline of vision of the operator between said support and said enlarginglens to confine largely through said lens the light emanating from saidsource of illumination, at least one of said walls being movable out oflightconfining position to expose fully the negative to the view of theoperator while said source of illumination is in non-intensifiedcondition and being movable into light-confining position when saidsource of illumination is intensified, a movable shutter normally in thepath of the light emanating from said lens, means for simultaneouslywithdrawing the shutter from the path of the light emanating from saidlens and for moving said movable wall into light-confining position, anda single manually manipulable means for actuating said last-named means.

6. In a photographic enlarging and printing machine, a transparent fiatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source ofillumination sufilcient to render visible to the operator the image on anegative placed on said transparent fiat support, means for intensifyingthe illumination for purposes of exposure, walls projecting downwardlyfrom said enlarging lens and substantially encompassing space in theline of vision of the operator between said support and said enlarginglens to confine largely through said lens the light emanating from saidsource of illumination, at least one of said walls being movable out oflightconfining position to expose fully the negative to the view of theoperator while said source of illumination is in non-intensifiedcondition and being movable into light-confining position when saidsource of illumination is intensified, a movable shutter normally in thepath of the light emanating from said lens, means for withdrawing theshutter from the path of the light emanating from said lens and formoving said movable wall into light-confining position simultaneouslywith the intensification of said source of illumination, and a singlemanually manipulable means for actuating said last-named means.

'7. In a photographic enlarging and printing machine, a transparent fiatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source. ofillumination suficient to render visible the image on the negative,means for intensifying the illumination for purposes of exposure, wallsprojecting downwardly from said enlarging lens and substantiallyencompassing space in the line of vision of the operator between saidsupport and said enlarging lens to confine largely through said lens thelight emanating from said source of illumination, at least one of saidwalls being of sufiicient light-transmitting properties to permit viewtherethrough of the highly illuminated negative but being movable out oflight-confining position to expose fully the negative to the view of theoperator while said source of illumination is in non-intensifiedcondition, a movable shutter normally in the path of the light emanatingfrom said lens, and means for simultaneously withdrawing the shutterfrom the path of the light emanating from said lens and for moving saidmovable wall into lightconfining position.

8. In a photographic enlarging and printing machine, a transparent flatsupport against which a negative may be placed, an enlarging lensimmovably fixed in spaced relationship from said support, a source ofillumination sufiicient to render visible the image on the negative,means for intensifying the illumination for purposes of exposure, wallsprojecting downwardly from said enlarging lens and substantiallyencompassing space in the line of vision of the operator between saidsupport and said enlarging lens to confine largely through said lens thelight emanating from said source of illumination, at least one of saidwalls being of sufficient light-transmitting properties to permit viewtherethrough of the highly illuminated negative but being movable out oflight-confining position to expose fully the .negative to the view ofthe operator while said source of illumination is in non-intensifiedcondition, a movable shutter normally in the path of the light emanatingfrom said lens, and means for withdrawing the shutter from the path ofthe light emanating from said lens and for moving said movable wall intolight-confining position simultaneously with the intensification of saidsource of illumination.

PAUL S. PIRMOV.

